I have rebuilt the scv, Bought orings a month back and finally got around to installing em a couple days ago, The rear backblade will leak down even if the engine is running, even before redoing the orings, If its running for example and I jump on the back blade a couple times (220ish pounds) and go to lift it will have lowered some, I attempted to raise the front end of the 425 to fix the deck with the 3point hitch and it did not even raise it half a inch, you could feel the weight go on the 400 but no lift? Any ideas? I have just changed the fluid (Even though its fluid from the 425, and flushed the filter) I am very tight on cash and can not afford to replace the fluid with new, It was doing this before the fluid change as well (Was running ATF)

I think there is air in the lines, since you recently worked on it, it raises the possibility of air in the lines. Just work the cylinder back foth a bunch of times to try and get the air out. Then see if it is any better.

Easy way to check for leaks is to get a large cardboard box, and flatten it out. then operate the tractor to normal operating temp (works for cars and trucks too) Parke the machine over night on the cardboard. Next day leaks are revieled.

Since you have very little pressure I wonder if your bypass or relief valve for the implement lift is malfunctioning. I know they sometimes stick and have to be serviced to get them working properly again. Check your private messages. I'm going to send you some info. that may help!